AFAIK,
Perhaps you can play with the recorded voice, there are many applications in the playback store that do the same, even creating a song from user voice input, so it’s quite possible to convert ordinary user voice input with some other tone and tempo, and those applications really funny if they are well developed.
To use it with Call, I think it will be impossible, and Android should / will never provide such an opportunity to the developer for this. "Everything for user security restrictions"
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